Method blockToCode

packages/blockly/core/generator.ts:234–288

* Generate code for the specified block (and attached blocks). * The generator must be initialized before calling this function. * * @param block The block to generate code for. * @param opt_thisOnly True to generate code for only this statement. * @returns For statement blocks, the g

(
    block: Block | null,
    opt_thisOnly?: boolean,
  )

   * operator order value.  Returns '' if block is null.
   */
  blockToCode(
    block: Block | null,
    opt_thisOnly?: boolean,
  ): string | [string, number] {
    if (this.isInitialized === false) {
      console.warn(
        'CodeGenerator init was not called before blockToCode was called.',
      );
    }
    if (!block) {
      return '';
    }
    if (!block.isEnabled()) {
      // Skip past this block if it is disabled.
      return opt_thisOnly ? '' : this.blockToCode(block.getNextBlock());
    }
    if (block.isInsertionMarker()) {
      // Skip past insertion markers.
      return opt_thisOnly ? '' : this.blockToCode(block.getChildren(false)[0]);
    }

    // Look up block generator function in dictionary.
    const func = this.forBlock[block.type];
    if (typeof func !== 'function') {
      throw Error(
        `${this.name_} generator does not know how to generate code ` +
          `for block type "${block.type}".`,
      );
    }
    // First argument to func.call is the value of 'this' in the generator.
    // Prior to 24 September 2013 'this' was the only way to access the block.
    // The current preferred method of accessing the block is through the second
    // argument to func.call, which becomes the first parameter to the
    // generator.
    let code = func.call(block, block, this);
    if (Array.isArray(code)) {
      // Value blocks return tuples of code and operator order.
      if (!block.outputConnection) {
        throw TypeError('Expecting string from statement block: ' + block.type);
      }
      return [this.scrub_(block, code[0], opt_thisOnly), code[1]];
    } else if (typeof code === 'string') {
      if (this.STATEMENT_PREFIX && !block.suppressPrefixSuffix) {
        code = this.injectId(this.STATEMENT_PREFIX, block) + code;
      }
      if (this.STATEMENT_SUFFIX && !block.suppressPrefixSuffix) {
        code = code + this.injectId(this.STATEMENT_SUFFIX, block);
      }
      return this.scrub_(block, code, opt_thisOnly);
    } else if (code === null) {
      // Block has handled code generation itself.
      return '';
    }
    throw SyntaxError('Invalid code generated: ' + code);
  }

  /**
   * Generate code representing the specified value input.